Exam 2 Lecture - Developmental Anatomy

Question 1

What are congenital defects?

Answer 1

defects that are present at birth

Question 2

What can cause congenital defects?

Answer 2

anything that the mother comes in contact with can affect the pregnancy; environmental, vaccines, medicines

Question 3

What is a critical period of development?

Answer 3

a point in time when we have an organ or an organ system developing

Question 4

When is a fetus the most susceptible to environmental influences?

Answer 4

during critical periods because they are undergoing a lot of replication

Question 5

What can disruption in one organ system lead to?

Answer 5

can impact the development of another organ systems

Question 6

True or False: Critical periods only occur in utero

Answer 6

False: they can occur post natally

Question 7

What is the cause of cycloptic lamb?

Answer 7

the ewe ingests the veratrum californicum at 14-15 days of gestation that can cause this defect

Question 8

What could cause cerebellar hypoplasia?

Answer 8

genetic reasons, infections, toxins

Specifically: bovine viral diarrhea and feline panleukopenia

Question 9

How can bovine viral diarrhea cause cerebellar hypoplasia?

Answer 9

If the cow is infected with BVD within 100-170 days of gestation the calf could be infected which in turn will cause cerebellar hypoplasia

Question 10

How can feline panleukopenia cause cerebellar hypoplasia?

Answer 10

If the queen gets infected with feline panleukopenia in the last part of gestation or the kitten gets infected within the first 14 days of birth the kitten can develop cerebellar hypoplasia

Question 11

Cells in the zygote are____.
(A) restricted
(B) unrestricted

Answer 11

unrestricted

Question 12

Why do cells become more restricted throughout development?

Answer 12

because their environment is changing and the cells that they are in contact with are changing

Question 13

True or False: Cells have the same DNA later in development that they had in early development

Answer 13

True: although the cells are more restricted later in development, their DNA does not change

Question 14

What is a zygote?

Answer 14

a really big cell

Question 15

What is the zona pellucida?

Answer 15

the glycoprotein covering that surrounds the zygote

Question 16

What is a cleavage?

Answer 16

it is where the zygote divides

Question 17

True or False: When the cell continues to divide, and the zona pellucida is still in place, the zygote grows to make space for the new cells

Answer 17

False

Question 18

When does the zygote become the morula?

Answer 18

when there are 16 blasomeres present

Question 19

What do the outer blastomeres of the morula become?

Answer 19

trophoblast cells which help form part of the placenta

Question 20

What do the inner blastomeres of the morula become?

Answer 20

contribute to the inner cell mass - embryo

Question 21

What blastomeres are the target of embryonic splitting

Answer 21

the inner blastomeres

Question 22

When does the morula become the blastula?

Answer 22

when the zona pellucida has broken down and the embryo begins to grow

Question 23

What is the purpose of the blastocoele?

Answer 23

to help facilitate diffusion

Question 24

When does gastrolation normally occur?

Answer 24

around 14 days into the gestational period

Question 25

Right before gastolation, what are the structures of the embryo?

Answer 25

amniotic cavity, yolk sac, bilaminar disc (embryo)

Question 26

What is the bilaminar disc made out of?

Answer 26

epiblast cells and hypoblast cells

Question 27

What is the purpose of gastrolation?

Answer 27

to give rise to three germ layers and marks the beginning of organ and body development

Question 28

What initiates gastrolation?

Answer 28

the formation of the primitive streak and the primitive node

Question 29

What is the importance of the primitive streak aside from initiating gastrolation?

Answer 29

it gives the embryo its polarity

Question 30

What forms the endoderm?

Answer 30

the wave of epiblast cells that flow deep through the primitive groove

Question 31

What forms the mesoderm?

Answer 31

the wave of epiblast cells that flow through the primitive groove but lay closer to it than the endoderm

Question 32

What forms the ectoderm?

Answer 32

the wave of epiblast cells that do not migrate at all

Question 33

Where is the notochord formed?

Answer 33

in the mesoderm

Question 34

What does the ectoderm become?

Answer 34

skin, neural tissue, skeletal and connective tissue of the head

Question 35

What does the mesoderm become?

Answer 35

muscle, skeleton, internal organs (specifically urogenital), cardiovascular season

Question 36

What does the endoderm become?

Answer 36

the lining of the digestive and respiratory tracts as well as the organs of digestion

Question 37

What initiates the creation of the coelom?

Answer 37

small vesicles called ceolomic vesicles

Question 38

Where are coelomic vesicles located?

Answer 38

within the mesoderm

Question 39

When these vesicles coalesque, what do they form?

Answer 39

the ceolem; the somatic layer and the splanchnic layer

Question 40

What does the somatic coelem become?

Answer 40

the body wall, adjacent to the ectoderm

Question 41

How does the somatic coelem grow?

Answer 41

ventrally and medially

Question 42

What does the splanchnic coelem become?

Answer 42

organs, adjacent to the endoderm, the primitive gut tube

Question 43

How does the splanchnic coelem grow?

Answer 43

ventrally and medially

Question 44

What is schistosmomus reflexus?

Answer 44

when the body wall never forms in utero; most common in cattle

Question 45

What are the 3 situations that can result in monozygotic twinning?

Answer 45

1. blastomeres split apart and form 2 completely separate embryos
2. two inner cell masses develop (share the same placenta)
3. No separation of the zygote or inner mass cells (share amniotic cavity and placenta; can lead to conjoined twins)

Question 46

What is an amorphous globosus?

Answer 46

a hairy glob of muscle and connective tissue that comes out after a calf has been born